Arrangement in tool changes for stamping and nibbling machines and the like

ABSTRACT

The present invention provides an automatic retooling means in machines working with two cooperating tools such as stamping, nibbling and like machines. The automatic retooling means provide for the transfer and return of pairs of tools from a magazine to their working position in a machine. The automatic retooling means include a plurality of superposed pairs of turret head plates to carry respective cooperating pairs of tools in the magazine in positions relative to their corresponding working position, and two parallel and simultaneously operating tool changing means arranged for transporting and returning the respective tools from the magazine to their working position in the machine.

United States Patent 1191 Kristiansson July 17, 1973 [75] Inventor: ErikKristiansson, Partille, Sweden [73] Assignee: Pullmax Aktiebolag,Gothenburgh,

Sweden [22] Filed: Oct. 7, 1970 [21] Appl. No.: 78,691

3,590,470 6/1971 Brainard 29/568 Primary ExaminerAndrew R. JuhaszAssistant Examiner-Z. R. Bilinsky Attorney-Hill, Sherman, Meroni, Gross& Simpson [57] ABSTRACT The present invention provides an automaticretooling means in machines working with two cooperating tools such asstamping, nibbling and like machines. The automatic retooling meansprovide for the transfer and return of pairs of tools from a magazine totheir working position in a machine. The automatic retooling meansinclude a plurality of superposed pairs of turret head plates to carryrespective cooperating pairs of tools in the magazine in positionsrelative to their corresponding working position, and two parallel andsimultaneously operating tool changing means arranged for transportingand returning the respective tools from the magazine to their workingposition in the machine.

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INVENTOR ERIK KRISTIANSSON BY v ATTORNEYS PATENTEDJULI 1197s saw a nr 3INVENTOR ARRANGEMENT IN TOOL CHANGES FOR STAMPING AND NIBBLING'MACHINES. AND THE LIKE The present invention refers to an arrangement intool changes for stamping and nibbling machines and the like.

When making recesses, notches, holes etc. in thin sheet metal in themanufacture of apparatus constructional elements for example, the. workis usually effected with stamping or nibbling machines. Of these, thestamping machine is the. mostproductive and gives the best result, sincethe resultingcut surfaces fulfill thehigh requirements placed on surfacesmoothness. On the other hand, nibbling machines can be. usedwhen thelength of the cut to be made is too large for stamping or when thecurvature of the cut is complicated or. if the number of notches,recesses, curved. profiles etc. to be made occur too seldom to makestamping an economically worthwhile alternative. The most suitablemachine for use in the present connection is therefore one which can beused for both stamping and nibbling.

Combined stamping and. nibbling machines commercially available atpresent are characterized. in that the change over from one tool toanother must be made manually. It is true that with the aid of certaindevices retooling can be eflected relatively quickly, but. this ingv andnibbling machines which eliminates the aforementioned limitations. 1

The invention. will now be described in more detail with reference tothe accompanying drawings, which does not eliminate the necessity ofhaving, amachine operator in attendance. Another disadvantage is thatthe machine operations can not be automated'in a purposeful manner, e.g.by numerical control. Machines. used solely for stamping and with themechanized tool. changing have long been known to the art. Thesemachines are normally constructed with a C-type or portal-type stand, inwhich two plates disposed one above the other and rotatable aboutacommon rotation shaft, so-called turret or revolving heads, arearranged. The upper and lower portions of the punches are attached tothe periphery of the turret heads. The turret heads can be rotated bymeans of special indexing mechanisms and locked in position when thecorrect tool is located beneath the hammer of the machine.

This type of retooling device has practical limitations, however.Because the turret heads are without exception always placed inside theimpact-load absorbing stand, the number of tool stations is restricted,among other things since an excessively large number of tools wouldresult in a stand of unreasonable dimensions. That this must be the casewill readily be perceived when it is remembered that the moment ofinertia of the stand beams must increase by a third power in relation tothe throat depth, presuming that thesarne static stiffness is to bemaintained at a given punching force. Furthermore, in order that theturret heads can be utilized to a maximum, the heads are designed for aspecific number of tools within each range of sizes, which means thatindexing can not be effected between equal pitch angles. It is obviousthat this greatly restricts selectivity with regard to the assortment oftools which may be used. A further limiting factor prevailing inretooling structures of this type is that tools can only be moved totheir working position while the. machine is stationary. Owing to thefact that the punching or stamping unit and tool turret heads mustalternately await each other, the machine as a whole operatesrelativelyslowly with respect to the production rate.

The present invention relates to an automatic. retooling means forstamping machines or combined stampdiagrammatically illustrate anembodiment of the invention; In the drawings, FIG. 1 illustrates in sideview the. front portion of a machine and a tool turret drive means. FIG.2 is a top plan view of the tool turret structure. FIG. 3 illustratesthe rear portion of the machine with the tool magazine seen from theside.

Positioned adjacent the working machine is a turrettype tool magazine.The magazine comprises an optional number of pairs of circular plates 1and 2 secured to a common hub 3. The hub is in the form of a cylinder,which is connected at its upper end with a splined shaft 5, via a cap 4.At the foot 7 of the magazine is secureda spindle '6, on which the hub 3can be moved axially with a sliding fit. The length of the spindle isadjusted to the length of the hub. The magazine can be raised andlowered vertically, by introducing a pressure medium between the cap 4and the spindle 6. This movement of the magazine can also be effected,however, by other means, such as worms, link systems andthe like. Inaddition, the tool magazine can be rotated and stopped in any desiredangular position, by means of a drive assembly 7a.

The circular plates are provided at the periphery thereof with recessesin theform of grooves, in which the upper portions 8 and lower portions9 of the punching tools can be'radially inserted. All upper portions 8(punches) have the same dimensions as the attachments. This is also truefor the lower portions 9 (the dies). A simple spring mechanism 9aprevents the tool portions from accidentally sliding out of the magazineas it rotates. The pairs of circular plates may also be provided withraised members or similar means for ensuring correct positioning of saidplates.

The tool turret structure comprises two superposed similar units locatedon one side of the working machine, above and below the stand throat.Each turret unit comprises two opposing slide systems 10 mounted on acommon hub 11. The tool turret heads can be rotated about the shafts 12.Running on each slide is a shuttle l3, radially maneuvered for example,by the hydraulic or compressed air cylinder 14. At the outer end of'eachtop turret shuttle 13 is mounted a swinging grip claw 15 adapted. forgripping the upper portion 8, the punch, of the punching tool. At theouter end of each lower turret shuttle 13 is mounted a similar swinginggrip claw 15' adapted for gripping the lower portion 9,

. the die, of the tool. The gripping claws have operating means 16. Thetop turret slides 10 are provided at their outer ends with recesses 17,recess gripping means 18 and operating means 19 for receiving the punch8 in a sliding fit within said recesses. The lower turret slides 10. areprovided at their outer ends with recesses 17, recess gripping means 18'and similar operating means 19 for stationarily receiving the die 9 inaxial alignment with punch 8. The turret heads can be rotated through ina swinging movement by drive means 20. The rest position of the turretsis shown in FIG. 2. The rotary movement of the turret heads isrestricted by means of dirigible locking pistons 21, which are securedto the machine stand and passed into positionfixing holes in engagingslides 10. The tool changing means operates in the following manner:

The tool magazine is assumed to be completely or partly full ofassembled and pre-set punching tools for cutting contours with varyingdimensions. When the working sequence is started, the magazine isrotated and, if required, lifted so that the correct tool is moved toposition I. The rearwardly directed shuttles 13 on the upper and lowerturret heads project out towards the tool magazine and, by means of theclaws 15, 15 grip at both the same time the tool punch and diepositioned in the magazine. The shuttles are then returned to theirstarting position, transporting the tool portions into abutment with thecup-shaped recess 17 of the slides. The gripping means 18 are thenclosed and complement with recess 17 the bearing positions for the shankof punch 8 in a manner whereby an accurate sliding fit is obtainedtherewith. Similarly the gripping means 18' close around the die 9 forreceiving the die in a stationary position relative to punch 8. Theupper and lower turret edges are then rotated through 180 around theshafts 12. The punch and die so received are then transferred toposition ll (FIG. 2) the working position and at the same time passesinto engagement with the rectilinear, oscillating upper tool attachmentof the working machine and with its stationary die holder. The lockingpistons 21 then engage the position-fixing holes to provide an exact,mutual positional setting of the upper and lower tool portions. Thegripping means 15 then open and release the movable tool portions. Theworkpiece is then placed in position, and the stamping operation iscarried out with the turret head as a tool guide. The opposing turrethead slide has, in the meanwhile, been turned rearwardly. If the slidehas a tool mounted therein, the tool is released, owing to the fact thatthe gripping means 18 opens and the shuttle 13 projects out and placesthe tool in the desired recess in the tool magazine. The gripping means15 releases its hold, whereafter the shuttle returns. The magazine thenplaces a new tool in position I and the sequence of operations is thenfully repeated.

As will be evident from the foregoing, the present invention constitutesa considerable advance when compared with the present state of the art.Because the tool magazine is placed alongside the working machine, themachine stand can be dimensioned quite independently of the number oftools desired. Tool selection is quite arbitrary, while retooling can beeffected very rapidly, owing to the fact that the tool magazine canposition the tool needed for the next machining operation in a state ofreadiness while the working machine continues to operate. A workingmachine equipped with the aforedescribed tool changing device can alsobe controlled to advantage by means of an appropriate, separate controlsystem, for example a numerical control system.

I claim:

1. A punch press comprising:

a. a working station including a ram and a bolster adapted to engagecoactive punch and die tooling;

b. a movable storage magazine receptive of coactive punch and dietooling;

c. a pair of tool transfer arms disposed between said working stationand said storage magazine and rotatable about a vertical axis with anend of each arm thus movable between a position adjacent to saidmagazine and a position where said end is aligned with said ram andbolster; and

d. means on each said arm for engaging with the tooling, said armsholding the tooling in coactive alignment during punching.

2. A punch press according to claim 1 in which said engaging meanscomprises: extendible tool gripping means carried on said arm, and fixedtool clamping means at said end of said arm, said tool gripping meansbeing operable for gripping and releasing the tooling in said magazinewhen extended, and for retractingly moving the tooling to said clampingmeans on said arm for punching.

3. A punch press according to claim 1 in which said storage magazine isrotatable about a vertical axis, said magazine having radially openingperipheral slots receptive of the tooling.

4. A punch press according to claim 3 in which said storage magazine hasa plurality of axially spaced sets of said peripheral slots, and meansfor shifting said magazine axially to align a selected group ofperipheral slots with said arms.

5. An automatic retooling means in machines working with two cooperatingtools such as stamping, nibbling and like machines, the tools beingtransferred by means of tool change over means from a turret-typemagazine arranged in connection with the machine to a working positionin said machine, said retooling means comprising a plurality ofsuperposed pairs of turret head plates arranged to carry respectivecooperating pairs of tools in the magazine in positions relative totheir corresponding working position, and two parallel andsimultaneously operating tool changing means being arranged fortransporting the respective tools from the magazine to the workingposition and vice versa, said turret head plates being arranged to becommonly rotated and moved in the direction of their axis of rotation tomove the respective cooperating pairs of tools to determined positionsto be gripped by the tool changing means and being fixed to a hub havingthe form of a cylinder and in which a piston is slidably accommodated,the piston being stationary and the hub capable of being moved axiallyin relation to the piston by introducing pressure medium above thepiston to place axially respective pairs of tools in gripping positions.

6. A means according to claim 5, wherein the tool magazine constructedof said turret head plates is arranged to place the tool pair for thenext following working operating in gripping position whilst a workingoperation is taking place in the machine.

7. A means according to claim 5, wherein the tool changing means isarranged to accommodate the gripped tools in guides which serve asguides for the tools during their working period in the machine.

8. A means according to claim 7, wherein the tool changing means isprovided with guide means for aligning and fixing the cooperating toolpair in working position.

1. A punch press comprising: a. a working station including a ram and abolster adapted to engage coactive punch and die tooling; b. a movablestorage magazine receptive of coactive punch and die tooling; c. a pairof tool transfer arms disposed between said working station and saidstorage magazine and rotatable about a vertical axis with an end of eacharm thus movable between a position adjacent to said magazine and aposition where said end is aligned with said ram and bolster; and d.means on each said arm for engaging with the tooling, said arms holdingthe tooling in coactive alignment during punching.
 2. A punch pressaccording to claim 1 in which said engaging means comprises: extendibletool gripping means carried on said arm, and fixed tool clamping meansat said end of said arm, said tool gripping means being operable forgripping aNd releasing the tooling in said magazine when extended, andfor retractingly moving the tooling to said clamping means on said armfor punching.
 3. A punch press according to claim 1 in which saidstorage magazine is rotatable about a vertical axis, said magazinehaving radially opening peripheral slots receptive of the tooling.
 4. Apunch press according to claim 3 in which said storage magazine has aplurality of axially spaced sets of said peripheral slots, and means forshifting said magazine axially to align a selected group of peripheralslots with said arms.
 5. An automatic retooling means in machinesworking with two cooperating tools such as stamping, nibbling and likemachines, the tools being transferred by means of tool change over meansfrom a turret-type magazine arranged in connection with the machine to aworking position in said machine, said retooling means comprising aplurality of superposed pairs of turret head plates arranged to carryrespective cooperating pairs of tools in the magazine in positionsrelative to their corresponding working position, and two parallel andsimultaneously operating tool changing means being arranged fortransporting the respective tools from the magazine to the workingposition and vice versa, said turret head plates being arranged to becommonly rotated and moved in the direction of their axis of rotation tomove the respective cooperating pairs of tools to determined positionsto be gripped by the tool changing means and being fixed to a hub havingthe form of a cylinder and in which a piston is slidably accommodated,the piston being stationary and the hub capable of being moved axiallyin relation to the piston by introducing pressure medium above thepiston to place axially respective pairs of tools in gripping positions.6. A means according to claim 5, wherein the tool magazine constructedof said turret head plates is arranged to place the tool pair for thenext following working operating in gripping position whilst a workingoperation is taking place in the machine.
 7. A means according to claim5, wherein the tool changing means is arranged to accommodate thegripped tools in guides which serve as guides for the tools during theirworking period in the machine.
 8. A means according to claim 7, whereinthe tool changing means is provided with guide means for aligning andfixing the cooperating tool pair in working position.